285,407 research outputs found

    Quantitative non-destructive testing

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    The work undertaken during this period included two primary efforts. The first is a continuation of theoretical development from the previous year of models and data analyses for NDE using the Optical Thermal Infra-Red Measurement System (OPTITHIRMS) system, which involves heat injection with a laser and observation of the resulting thermal pattern with an infrared imaging system. The second is an investigation into the use of the thermoelastic effect as an effective tool for NDE. As in the past, the effort is aimed towards NDE techniques applicable to composite materials in structural applications. The theoretical development described produced several models of temperature patterns over several geometries and material types. Agreement between model data and temperature observations was obtained. A model study with one of these models investigated some fundamental difficulties with the proposed method (the primitive equation method) for obtaining diffusivity values in plates of thickness and supplied guidelines for avoiding these difficulties. A wide range of computing speeds was found among the various models, with a one-dimensional model based on Laplace's integral solution being both very fast and very accurate

    Robotic Non-Destructive Testing

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    Non-destructive testing (NDT) and evaluation (NDE) are commonly referred to as the vast group of analysis techniques used in civil, medical, and industrial sectors to evaluate the properties of materials, tissues, components, or structures without causing any damage [...]

    Shape-based defect classification for Non Destructive Testing

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    The aim of this work is to classify the aerospace structure defects detected by eddy current non-destructive testing. The proposed method is based on the assumption that the defect is bound to the reaction of the probe coil impedance during the test. Impedance plane analysis is used to extract a feature vector from the shape of the coil impedance in the complex plane, through the use of some geometric parameters. Shape recognition is tested with three different machine-learning based classifiers: decision trees, neural networks and Naive Bayes. The performance of the proposed detection system are measured in terms of accuracy, sensitivity, specificity, precision and Matthews correlation coefficient. Several experiments are performed on dataset of eddy current signal samples for aircraft structures. The obtained results demonstrate the usefulness of our approach and the competiveness against existing descriptors.Comment: 5 pages, IEEE International Worksho

    Non-destructive testing of composite plates by holographic vibrometry

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    We report on a wide-field optical monitoring method for revealing local delaminations in sandwich-type composite plates at video-rate by holographic vibrometry. Non-contact measurements of low frequency flexural waves is performed with time-averaged heterodyne holography. It enables narrowband imaging of local out-of-plane nanometric vibration amplitudes under sinusoidal excitation, and reveals delamination defects, which cause local resonances of flexural waves. The size of the defect can be estimated from the first resonance frequency of the flexural wave and the mechanical parameters of the observed layer of the composite plate

    Non-destructive Testing of Pipelines

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    This paper shall present different, contemporarily available non-destructive testing (NDT) methods of pipelines and compare them to each other from the technical and economical point of view. An evaluation of their suitability for CERN activities, based on the opinions and experience of various specialists at CERN (LHC, ST, TIS), is also introduced

    Destructive and Non - destructive Testing of Concrete Structures

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    The estimation of mechanical properties of concrete can be carried out by several methods; destructive and non-destructive. In this context, the crushing of the samples is the usual destructive test to determine the concrete strength. The rebound hammer test and the ultrasonic device are used in the field of non-destructive tests to determine respectively the compression strength and the ultrasonic pulse velocity (UPV) in the concrete. In this work, eight concrete compositions were used to prepare cylindrical specimens (16 cm x 32 cm) by varying the water/ cement ratio and the cement dosage. An experimental study was conducted to determine the compressive strength of concrete by destructive (compression) and non-destructive (rebound hammer) tests at different ages (7, 14 and 28 days). In addition, the influence of several factors on the modulus of elasticity determined by pulse velocity test was investigated. These factors mainly included the age of concrete and the water/ cement ratio. The results showed that the difference between the resistance values obtained by destructive and non-destructive methods decreases with increasing age of concrete. The dynamic modulus of elasticity increases with the curing time of the concrete until the age of three months. In addition, a simplified expression has been proposed to estimate the rebound number from the value of the dynamic modulus of elasticity determined by pulse velocity test

    System of Non-Destructive Testing

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    In this paper the initial analysis of NDT laboratory is presented by means of agent-based modelling. For the purpose of analysis, laboratory is taken into account as a complex system consisting of three agents; equipment, personnel and specimens. Interaction between the agents is circular. In that sense, the agents are mutually interconnected in a way that one agent simultaneously interacts with others. According to the interactions specific for NDT laboratories, the response of total testing time is presented considering various number of laboratory personnel while each operator has different skills and ability. Agent personnel has to perform testing of specimens. Since the complexity of specimens is quite diverse the specimens are represented as an agent. Additionally, during the whole time sequence of testing a certain specimen, operator is using NDT equipment relevant for the testing method, while the particular time of usage of the equipment can be shorter than the whole testing time. Availability of the equipment is therefore another agent. The evaluated outcome is the total testing time. Presented results are obtained carrying out a simulation by means of multi-agent modelling and simulation tool named “ENTORAMA”. Finally, the overall laboratory\u27s performance is given in the respect of the number and structure of the laboratory personnel

    Non Destructive Testing and Evaluation

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    Nondestructive testing (NDT), also called nondestructive evaluation (NDE) and nondestructive inspection (NDI), is testing that does not destroy the test object. The activ-ity primarily involves looking at (or through) or meas-uring something about an object to determine some property of the object or to determine whether the object contains irregularities, discontinuities, or flaws. The terms irregularity, discontinuity, and flaw can be used inter-changeably to mean something that is questionable in the part or assembly, but specification, codes, and local usage can result in different definitions for these terms. As all these terms describe what is being sought through testing, inspection, or examination, the term NDE (non-destructive evaluation) has come to include all NDE used to find, locate, and sizing flaws and allow the investi-gator to decide whether or not the object or flaws are acceptable.A flaw that has been evaluated as rejectable is usually termed a defect

    Inspection and diagnosis tests for structural safety evaluation: A case study

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    Diagnosis and assessment of existing structures is a developing area due to the appearance of a high number of building defects, structural and non-structural deterioration and precocious loss of quality, and, consequently, lower expected durability. With the aim of verifying the viability of rehabilitation or the need to demolish an existing fifteen year old parking building, several inspections and diagnostic non-destructive and destructive testing, visual inspection, were carried out to evaluate the structural safety conditions

    Apprenticeship Standard : Non-Destructive Testing Engineer

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    High-efficiency video compression technology is of primary importance to the storage and transmission of digital medical video in modern medical communication systems. To further improve the compression performance of medical ultrasound video, two innovative technologies based on diagnostic region-of-interest (ROI) extraction using the high efficiency video coding (H.265/HEVC) standard are presented in this paper. First, an effective ROI extraction algorithm based on image textural features is proposed to strengthen the applicability of ROI detection results in the H.265/HEVC quad-tree coding structure. Second, a hierarchical coding method based on transform coefficient adjustment and a quantization parameter (QP) selection process is designed to implement the otherness encoding for ROIs and non-ROIs. Experimental results demonstrate that the proposed optimization strategy significantly improves the coding performance by achieving a BD-BR reduction of 13.52% and a BD-PSNR gain of 1.16 dB on average compared to H.265/HEVC (HM15.0). The proposed medical video coding algorithm is expected to satisfy low bit-rate compression requirements for modern medical communication systems
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